Length Converter
How the conversion works
Every unit is converted through the metre, the SI base unit of length. Since the 1959 international yard and pound agreement, imperial and US units are defined exactly in metric terms, so these factors are not approximations:
| Unit | Exact value in metres |
|---|---|
| 1 inch (in) | 0.0254 m |
| 1 foot (ft) = 12 in | 0.3048 m |
| 1 yard (yd) = 3 ft | 0.9144 m |
| 1 mile (mi) = 1,760 yd | 1,609.344 m |
| 1 nautical mile (nmi) | 1,852 m |
To convert, the calculator multiplies your value by the first unit's factor and divides by the second's. For example 10 km = 10,000 m ÷ 1,609.344 = 6.21 miles.
Everyday reference points
- A marathon is 42.195 km, or 26.22 miles.
- 1.80 m in feet and inches: 1.80 ÷ 0.3048 = 5.91 ft, i.e. 5 ft and 0.91 × 12 ≈ 11 in.
- A 55-inch TV screen measures 139.7 cm diagonally.
- Nautical miles are used at sea and in aviation because one nautical mile corresponds to one minute of latitude; a knot is one nautical mile per hour.
Mental shortcuts
- km → miles: multiply by 0.6 and add a little (10 km ≈ 6.2 mi). Miles → km: multiply by 1.6.
- Consecutive Fibonacci numbers are close to the km/mile ratio: 3 mi ≈ 5 km, 5 mi ≈ 8 km, 8 mi ≈ 13 km.
- Inches → cm: multiply by 2.5 for a quick estimate, 2.54 for the exact answer.
Pick any pair of units above; the table under the result lists common values so you can read several conversions at once. For surfaces, use the area converter — area factors are the square of length factors.
Frequently Asked Questions
How many kilometres are in a mile?
Exactly 1.609344 km. Conversely, one kilometre is about 0.621 miles.
How do I convert my height into feet and inches?
Convert to feet, then multiply the decimal part by 12. For 1.75 m: 5.74 ft, i.e. 5 ft and 0.74 × 12 ≈ 9 in.
Is a UK mile the same as a US mile?
Yes. Both use the international mile of 1,609.344 m. Only the US survey mile, now retired, differed by a few millimetres.